Followers

September 10, 2008

Some of the sandbars and beaches built up in the March high-flow release are back to pre-flood levels.

By CYNDY COLEArizona Daily Sun

A half-year after a manmade flood built bigger sandbars and beaches in the Grand Canyon that are boon to native fish and plants, U.S. Geological Survey researchers say beaches are again eroding.

The data at this point is incomplete, researchers say, but some of the photos to date point to eroding sand bars as water releases from Glen Canyon Dam vary to meet peak power demands and interstate water-sharing agreements. A group of federal agents, tribes, environmentalists and power agencies that advises the Interior Department on how the Colorado River in Grand Canyon should be managed is meeting in Flagstaff Tuesday and today to discuss the latest research and propose next steps.

A budget up for discussion by the group today could determine whether there are any more experimental floods in the next five years. The next one called for in an earlier report by the Bureau of Reclamation is not until 2012.

About $3.3 million is projected to be spent on USGS research related to the flood this year and next.

The amount of sand in the Colorado River is of interest because it is believed to be linked to the creation of backwaters that could help promote the survival of some fish species, and because boaters use beaches for camping.

All of the sand that once flowed into the lower Colorado River upstream of Lake Powell is now trapped by the dam, leaving it to the remaining tributaries to supply sand to the main channel during periods of high water.

The advisory group did some battle publicly this spring, when Grand Canyon Superintendent Steve Martin proposed more regular floods to improve the canyon's ecosystem, to the disagreement of power producers and his bosses.

The floods are conducted as part of an experimental program to manage the Grand Canyon ecosystem to allow for power generation at the dam, while offsetting the dam where possible.

USGS researchers say it is possible to maintain some sandbars and beaches along the Colorado River with the dam in place.

But for that to happen, according to researchers' findings, power production would often suffer.

Environmental groups, including the Grand Canyon Trust, have litigated over dam operations, saying what's beneficial for peak power production puts some of the canyon's few remaining endangered fish species in jeopardy.

Trust employee Nikolai Lash, who works on this issue, said it's hopeful that the coming presidential election could change the Colorado River.

"The orientation has been completely backwards," he said. "This dam has been operated not for the benefit of Grand Canyon, but for the benefit of hydropower interests."

The third experimental flood since 1996, the March experiment was timed to move around three times more sand than was available in the tributaries to the Colorado River in 2004.